Presently, drives provided with toothed belts are used between gears with parallel rotation axes.
Such a parallelism has very narrow limits to grant the utmost endurance and reliability. This is particularly true at very high revolving speeds of the shafts. In fact, at very high revolving speeds a toothed belt drive between oblique shafts causes the wear of the belt in a very short time, even in the case where the guide rollers are placed on the two branches of the belt. Therefore, drives between oblique or orthogonal shafts up to now have required various complex and expensive kinematic systems.